Shaft furnace feeding device and method



Feb. 25, 1969 R. E. BLAU ET AL 3,29,463

SHAFT FURNACE FEEDING DEVICE AND METHOD Filed April 28, 1966 Sheet of5 lINVENTORS ROBERT E. BLAU GEORGE E. STONE mm qflmeq,

ATTORNEYS Feb. 25, 1969 R. E. BLAU ET AL 3,429,463

SHAFT FURNACE FEEDING DEVICE AND METHOD Filed April 28, 1966 Sheet 2 ofs Qfi H IENTORs ROBERT E. BLAU v GEORGE E STONE ATTORNEYS Feb. 25, 1969R. E. BLAU ET SHAFT FURNACE FEEDING DEVICE AND METHOD Sheet .&

Filed April 28, 1966 l ZNVENTORS ROBERT E. BLAU GEORGE E. STONEATTORNEYS States Int. Cl. FZSk 3/00; 365g 65/30, 29/00 ite ABSTRACT OFTHE DISCLOSURE A feeding device for shaft furnaces and the likeincluding a feed hopper and means for shuttling the hopper along a fixedpath. Discharge means are associated with the hopper and adapted todischarge feed material from the hopper into the furnace. The dischargemeans is rotatable, and there are means associated With the feedingdevice to correlate the shuttling movement of the hopper and therotation of the discharge means.

This invention relates generally as indicated to a feeding device forshaft furnaces or the like and more particularly to such a device whichincludes a unique combination of a shuttling feed hopper and a rotatabledis charging mechanism.

In the operation of any shaft furnace or kiln or any other similarapparatus wherein the material being treated continuously moves down ahollow shaft, one of the principal problems encountered is that ofobtaining uniform exposure of the downward moving feed material to theupward flowing hot gases which are used to achieve the desired heatingof the feed material. In order to accomplish such uniform exposure, itis necessary to provide uniform and continuous interstitial spacesthroughout the burden in the shaft of the furnace, or in other words,the porosity of the feed material in the furnace must be maintained asconstant as possible across the entire crosssection.

Generally, the prior attempts to obtain such constant or uniformporosity have consisted of presizing the feed material within closedimensional ranges, as for example in shaft kilns for producing highquality lime for structural purposes, the kilns are fed with large lumpsof limestone having their maximum dimensions ranging between about IOand 5". Similarly, in other shaft kilns producing lime, the limestonefeed is generally sized between about 5" and 2%. or between about 3" and1 /2, and iron oxide pellets, for example, are generally sized fromabout as" to about /2" for the initial heat treatment in shaft furnacesand for their ultimate use in blast furnaces.

Consequently, in all such furnace operations, the feed material isclosely sized to the extent possible to provide a maximum of continuousinterstitial space between the pieces of feed material to thus permit anunrestricted flow of gases through the burden within the furnace.

There is a practical limit, however, as to the accuracy of suchpre-sizing operations and also as to the narrowness of the size rangewhich is possible with any feed material. Accordingly, a secondrequirement in the feeding of shaft furnaces or the like is that thefeed be introduced into the furnace in such a manner that segregation ofthe smaller pieces from the coarse pieces is reduced as much aspossible. To achieve such uniform distribution of particle size in thefeed material, several devices have been known heretofore includingthose utilizing a bell type feeding system such as exemplified in US.Patents 1,928,039 and 2,408,945. While devices of this type have metwith some success, particularly in feeding cylindrical furnaces ofcircular cross-section, such systems have not atent 3,429,453 PatentedFeb. 25, 1969 vices are unsuitable for use with furnaces of othercrosssections as for example rectangular or elliptical as they do notprovide a uniform distribution of the feed material over the entirecross-section of the furnace. It is accordingly a principal object ofthe present invention to provide a feeding device whereby such problemsare overcome, and which is particularly suitable for feeding furnaces ofrectangular or elliptical cross-section.

It is an additional object of the present invention to provide a feedingdevice which is capable of providing a uniform and continuous supply ofmaterial without segregation of the material into different sizes.

Yet another object of the present invention is to provide a feedingdevice for shaft furnaces or the like in which a constant and uniformflow of material is maintained from the supply location to such furnace.

An additional object of the present invention is to provide such adevice whereby supply material may be fed in briquette form to a shaftfurnace or kiln with a minimum of breakage of the briquettes.

Other objects, features and advantages of this invention will becomeapparent to those skilled in the art after a reading of the followingmore detailed description.

These and other objects are achieved by this invention in which afeeding device for shaft furnaces is provided which includes a feedhopper which is designed to shuttle along a fixed path above such afurnace and which has a rotatable vertical spout suspended therefrom andadapted to discharge feed material into the furnace. The shuttlingmovement of the feed hopper and the rotation of the spout are correlatedin such fashion that when the shuttling movement is completed, therotation mechanism of the spout is actuated to rotate the spout, andwhen this movement is completed, the shuttling mechanism is in turnactuated to resume shuttling of the feed hopper along the fixed path.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawing setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of but afew of the various ways in which the principle of the invention may beemployed.

In said annexed drawings:

FIG. 1 is a schematic illustration of an illustrative burning processutilizing a shaft furnace in which the feeding device of this inventionmay be employed;

FIG. 2 is a view illustrating the feeding device in more detail;

FIG. 3 is a top plan view of the feeding device taken along line 33 ofFIG. 2;

FIG. 4 is a side view of the feeding device taken along the line 4-4 ofFIG. 2; and

FIG. 5 is a schematic view illustrating generally the movement of theshuttling device and the path of movement of the rotary spout, as willbe explained in more detail.

Referring to the drawings and more particularly to FIG, 1 thereof, asupply of feed rnaterial designated by numeral 1 is taken from a feedpreparation lant (not shown) to a moving screen 2 wherein material ofunacceptable size is separated out. The acceptable material is taken toa surge bin 3 which, preferably as illustrated has a plurality of levelindicating devices 4, 5 and 6 positioned at various heights therein toassist in maintaining a full charge within the bin at all times. Thelevel indicating devices are also, of course, correlated with controlmeans to maintain a constant supply of material entering and leaving thebin. The supply material is removed from the bottom of the surge bin toa second feeder screen 7 where further classification of the materialtakes place. After such classification, the supply material is fed intothe upper surface of shuttling feed hopper 8, which shuttles back andforth along a fixed path, as illustrated in more detail in the otherfigures, through a sprocket type drive mechanism shown generally by thenumeral 9.

The shuttling feed hopper is equipped with a rotatable verticallysuspended discharge means 10 which discharges the material into a shafttype kiln 11. The kiln is equipped with an exhaust duct 12 for exit ofthe upward flowing heating gases. After passing downwardly through theshaft kiln, the material is removed therefrom at 13 and fed into aclinker bin 14, after which it will be removed and subjected to furtherprocessing as is necessary.

Referring more particularly now to FIGS. 24 inclusive, the feedingdevice 8 and the rotatable discharge mechanism 10 are shown in moredetail. The feed hopper is shown as being suspended from a pair ofsupport beams and 21 by hanger rollers 22 which are generally U-shaped(see FIG. 4) and have rollers on opposite sides of the supporting beams.Also associated with the hopper is a drive mechanism indicated generallyby numeral 23 and which comprises a pair of drive chains 24 and 25 whichare anchored to the beams 20 and 221 respectively by means 26 and 27positioned on the support beams at the opposite ends of the path ofmovement of the hopper as it shuttles from side to side. The chains aretrained over sprockets 28, 29 and 30. The drive mechanism is actuated bya motor 31 to cause the hopper to shuttle from one side of the track tothe other.

Also associated lWltl'l the feed hopper is the rotatable dischargemechanism, indicated generally by the numeral 10, which is in the formof a rotatable vertical spout suspended from the bottom of the feedhopper. The spout is thus in communication with the feed hopper and isadapted to discharge material from the hopper into the furnace 11. Thespout has a vertical shaft 35 attached thereto through bars 35 and 35"which extends upwardly therefrom for assisting in suspending andstabilizing the spout. The rotation means for the spout is designatedgenerally by numeral 36; since this is a conventional mechanical meansand is not per se a part of the invention, it will not be described indetail herein.

To accommodate the drive mechanism for the rotatable spout, the feedhopper '8 is preferably designed so that it has a pair of dischargeopenings 37 and 38 at the bottom thereof which communicate with thespout to feed material thereto on opposite sides of the drive mechanism.Such construction has the advantage that it tends to assist in providinga uniform and constant flow of supply material to the spout and also toavoid clogging or bridging of material within the hopper. The dischargeopenings also preferably have means 40 and '41 positioned therein tocontrol the flow of material to the spout, which are preferably in theform of shutolf gates or gate valves.

A preferred mode of operation of the feeding device will now bedescribed. After the feed material has been supplied to the feed hopper,as for example in the manner shown in FIG. 1, the feed hopper isactuated so that it traverses the fixed path along the support beams 20and 21 and material is discharged into the furnace from the dischargeend of the spout. When the hopper reaches the end of its traverse in onedirection, as shown by the phantom line in FIG. 2, a limit switch 42positioned on the beam 20 is contacted by means 43 associated withhanger roller 22 to stop the movement of the feed hopper in thatdirection. The switch 42 is correlated with the drive mechanism for therotatable spout by standard means, preferably electrical, (as showndiagrammatically in FIG. 2), although it may alternatively bemechanical, pneumatic or hydraulic if desired, whereby when theshuttling action is stopped, the drive mechanism for the spout isactuated to cause the spout to rotate through a predetermined rotationmovement. When the rotation movement has been completed, it will in turnactuate the shuttling mechanism to cause the feed hopper to reverse itsdirection of travel and to return to its original position adjacent theopposite end of beams 20 and 21 (the FIG. 2 position). A limit switch 44and stop means 45 are also, of course, positioned at this end of thebeam so that the shuttling movement will be stopped and the rotationmovement of the spout actuated when the hopper reaches this position inits fixed path of travel.

As shown more clearly in FIG. 4, the discharge end 50 of the spout isoffset at an angle with respect to the longitudinal axis of the spout sothat the feed material will not be discharged centrally of the spout,which will assist in preventing a build up or heaping of the materialwithin the furnace as would occur if a central discharge were provided.Thus, as shown in FIG. 5, the discharge end 50 revolves through anapproximate elliptical path as the spout rotates. The phantom line 51represents the path of movement of the center line of the discharge endof the spout as the feed hopper shuttles along its fixed path. Thephantom illustration on the righthand side of the figure, of course,illustrates the path of rotation movement of the angular discharge whenthe feed hopper and spout have moved to the opposite end of the path.

The spout is preferably designed such that one complete rotationmovement will rotate the spout through thus to provide a more uniformdistribution of the feed material across the top of the kiln. The spoutmay, of course, be designed to undergo any selected degree of rotation,but it has been found that 180 is a preferred movement as betterdistribution of the feed material is obtained. Similarly, because ofthis same objective, the rotation movement of the spout is preferablydesigned to occur when the feed hopper has reached the permissible limitof its travel in one direction, but it is to be understood that therotation could be caused to occur at any position along the path oftravel and that such variation is within the scope of this invention.

As mentioned previously, the present invention is suitable for generalutility in supplying material to any hollow shaft, as for example, shaftfurnaces or kilns, but it may also be used in similar environments as insupplying materials to silos, drying shafts, gas generators or the like.The invention is particularly suitable, however, for use with shaftfurnaces such as blast furnaces, lime kilns and the like.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

We therefore particularly point and distinctly claim as our invention:

1. A feeding device for shaft furnaces or the like comprising a feedhopper, means for shuttling said hopper along a fixed path, a verticalspout suspended from said hopper into a furnace or the like, means torotate said spout, and means correlating the shuttling movement of saidhopper with the rotation of said spout whereby completion of shuttlingmovement actuates said rotation meass to rotate said spout andcompletion of rotation of said spout actuates said shuttling means toagain shuttle said hopper.

2. The feeding device of claim 1 in which said spout rotates 180 in onerotation movement.

3. The feeding device of claim 1 in which said spout has an angularopening at its discharge end.

4. The feeding device of claim 1 in which said hopper has a plurality ofdischarge openings at its lower end communicating with said spout tofeed material thereto.

5. The feeding device of claim 4 in which the means for rotating saidspout are positioned vertically above said spout and said dischargeopenings are positioned on 0pposite sides of said rotation means to feedmaterial to said spout.

6. The feeding device of claim 1 including means in said feeder hopperto control the flow of material to said spout.

7. A feeding device for shaft furnaces or the like comprising a feedhopper, means for shuttling said hopper along a fixed path, a verticalspout suspended from said hopper adapted to discharge feed material fromsaid hopper into a furnace or the like, means associated with said spoutfor rotation of said spout, and means correlating the shuttling movementof said hopper With the rotation of said spout whereby completion of theshuttling movement of said hopper to one end of said fixed path actuatessaid rotation means to rotate said spout through one complete rotationmovement and completion of such rotation movement of said spout in turnactuates said shuttling means to shuttle said hopper to the opposite endof said fixed path.

8. The feeding means of claim 7 in which said spout rotates through 180in one rotation movement.

9. A feeding device for shaft furnaces or the like comprising a feedhopper, means for shuttling said hopper along a fixed path, a rotatabledischarge means connected to said hopper adapted to discharge feedmaterial from said hopper into a furnace or the like, and meansassociated with said hopper and said discharge means to correlate theshuttling movement of said hopper with the rotation of said dischargemeans whereby completion of shuttling movement actuates the rotation ofsaid discharge means and completion of rotation of said discharge meansactuates said shuttling means to again shuttle said hopper.

10. In a process of feeding a uniform supply of material to a shaftfurnace or the like, the steps comprising shuttling a feed hopper havinga discharge means connected thereto along a fixed path, interruptingsuch shuttling movement of such hopper when such hopper is positionedadjacent one end of such fixed path, rotating such discharge meansduring such interruption, and subsequently resuming shuttling of suchhopper upon completion of rotation of such discharge means.

rotated through 180 during one rotation movement.

References Cited UNITED STATES PATENTS 6/1909 Korting 214 7/1913 Murray.

ROBERT G. SHERIDAN, Primary Examiner.

US. Cl. X.R. 214-17, 152

